Deposited-energy values and 3D-localization of the \(\gamma \) -ray hit position in each LaCl\(_{3}\) (Ce) crystal are necessary to apply the Compton scattering law on an event-by-event basis and obtain information on the incoming \(\gamma \) -ray direction [1]}.
An energy calibration of every i-TED PSD in the energy range between 122 keV and 1408 keV was performed by placing a \(^{152}\) Eu radioactive source near both detection planes. Additionally, the intrinsic \(\alpha \) -activity of the LaCl\(_{3}\) (Ce) crystals [2]} was used to extend the calibration range up to 2.8 MeV. Finally, capture \(\gamma \) -ray spectra of the gold and iron samples measured at CERN n_TOF with i-TED were used, in combination with a MC-simulation of the capture-cascades, to extend the calibration range up to 7.6 MeV. A combination of two second-degree polynomials were used as energy-calibration function for each PSD in the full energy range of the neutron-capture experiments. Energy resolutions between 7% and 5% fwhm at 662 keV have been found for the crystals placed in the S- and in the A-layers, respectively. Operating both layers in time-coincidence mode, a resolution of \(\sim \) 7% fwhm was found at 662 keV for the add-back spectrum of a \(^{137}\) Cs source (see Fig. REF ).
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